Viruses, especially bacteriophages are thought to have important functions in the deep-sea ecosystem, but little is known about the induction mechanism of benthic phages towards environmental change. Our prior work characterized a cold-active filamentous phage SW1 which infects the deep-sea bacterium Shewanella piezotolerans WP3; however, the underlying mechanism of this putative thermo-regulated genetic switch of SW1 is still unclear. In this study, the DNA copy number and mRNA abundance of the deep-sea phage SW1 were quantified in the whole life cycle of its host S. piezotolerans WP3 at different temperatures. Our results demonstrated that the induction of SW1 is dependent on a threshold temperature (4 °C), but this dependency is not proportional to temperature gradient. The RNA-Seq analyses revealed two highly transcribed regions at 4 °C and verified the presence of the long 3’UTR in SW1 genome. Interestingly, recruitment analysis showed that SW1-like inoviruses prevail in deep-sea (depth > 1000 m) and photic epipelagic and mesopelagic zones (depth < 1000 m), which suggested that the thermo-regulated genetic switch revealed in SW1 may be widely distributed in the ocean.

中文翻译：

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深海丝状噬菌体SW1的温度调节遗传开关及其在太平洋中的分布。

病毒，特别是噬菌体被认为在深海生态系统中具有重要功能，但对底栖噬菌体对环境变化的诱导机制知之甚少。我们先前的工作是研究一种冷活性丝状噬菌体SW1，该噬菌体感染深海细菌嗜热希瓦氏菌WP3。然而，SW1的这种推测的温度调节遗传开关的潜在机制仍不清楚。在这项研究中，深海噬菌体SW1的DNA拷贝数和mRNA丰度在宿主寄主S.zozolerlerans的整个生命周期中进行了定量。WP3在不同温度下。我们的结果表明，SW1的感应取决于阈值温度（4°C），但这种依赖性与温度梯度不成比例。RNA-Seq分析揭示了在4°C时两个高度转录的区域，并验证了SW1基因组中存在长3'UTR。有趣的是，募集分析表明，SW1样病毒在深海（深度> 1000 m）和上表层和中弹性带（深度<1000 m）地区盛行，这表明SW1中揭示的温度调节遗传开关可能广泛分布在海洋中。